Email List Normalizer

Paste a list of email addresses to deduplicate, strip Gmail dots and plus aliases, lowercase, and validate format. Download the cleaned list.

Input (one email per line)
Cleaned Output
Paste a list of email addresses to normalize and deduplicate.

How to Use the Email Normalizer

  1. Paste your email list — one email per line in the input area. The tool also handles comma-separated and semicolon-separated lists.
  2. Choose normalization options — toggle Lowercase, Deduplicate, Strip Gmail dots, Strip plus aliases, and Remove invalid as needed.
  3. View results — the cleaned list appears on the right with statistics showing how many duplicates and invalid addresses were found.
  4. Copy or download — use the buttons to export your cleaned list.

Why Normalize Email Lists?

Raw email lists collected from forms, spreadsheets, CRMs, or data exports frequently contain duplicates, case variations, and format inconsistencies that can cause problems when importing into email marketing platforms, databases, or analytics systems. Duplicate emails result in the same person receiving multiple copies of your emails, which increases unsubscribe rates and spam complaints. Case inconsistencies ([email protected] vs [email protected]) cause duplicate entries when email addresses are used as unique identifiers or primary keys.

Gmail Dot Aliasing

Gmail treats dots in the local part of an address as insignificant. The addresses [email protected], [email protected], and [email protected] all deliver to the same inbox. Users who want to create multiple accounts with slight variations often exploit this. When building a list of unique users, you need to normalize Gmail addresses by removing all dots from the local part. This tool applies that normalization only to Gmail domains (gmail.com and googlemail.com) since dots are meaningful for other providers.

Plus Aliasing (Subaddressing)

Email subaddressing (RFC 5321) allows adding a "+tag" suffix to the local part: [email protected] delivers to [email protected]. This feature is supported by Gmail, Outlook, Yahoo, ProtonMail, Fastmail, and many others. While it is a legitimate way to filter emails, it is also commonly used to sign up for free trials multiple times or to create multiple accounts. Stripping the plus suffix normalizes these aliases back to their canonical form.

Email Validation

The Validate mode checks each address against a standard email format regex (RFC 5322-compliant pattern). It identifies addresses that are clearly invalid due to missing @ symbols, missing domains, invalid characters, or other format errors. Note that format validation cannot determine if an address is active or if the mailbox exists — for that, you would need SMTP verification, which requires a server. Related tools: List Deduper, Word Counter.

Frequently Asked Questions

Gmail ignores dots in the local part. So [email protected], [email protected], and [email protected] all go to the same inbox. This tool removes dots from Gmail local parts to normalize them to a canonical form.
Gmail (and many other providers) ignore everything after a "+" in the local part. So [email protected] and [email protected] both deliver to [email protected]. This tool strips the plus alias suffix to reveal the canonical address.
Gmail, Outlook/Hotmail, Yahoo Mail, ProtonMail, Fastmail, and many others support plus aliasing (subaddressing). The RFC 5321 specification permits it and most major providers have implemented it.
Compare mode accepts two email lists and shows emails in A only, in B only, and in both. Useful for finding subscribers who unsubscribed, comparing import files, or identifying overlap between customer segments.
No. All processing happens entirely in your browser. Your email addresses never leave your device. There is no server, no logging, and no data storage of any kind.